Concerns have been raised over a bill introduced to the House of Lords that seeks to ban so-called conversion therapy.

The Private Members' Bill from Lib Dem peer Baroness Burt of Solihull wants "to prohibit sexual orientation and gender identity conversion therapy".

It had its first reading in the House of Lords on Monday. While private members' bills rarely become law, they can draw attention to their causes.

The bill proposes unlimited fines for those who offer "any practice" that assumes "any sexual orientation or gender identity is inherently preferable to another", and intends to "change" or "suppress" these.

Announcing her bill, Baroness Burt, who is the Lib Dem Lords spokesperson for equality, said: "It is very disappointing that the Conservatives have failed to deliver on their promise to ban conversion therapy for five years now. But we Liberal Democrats are more than willing to help them out by introducing the bill ourselves.

"There is cross-party consensus for dealing with this awful practice and I look forward to working with colleagues across Parliament to deliver the change we all desperately want to see - finally banning conversion therapy."

The Conservative government first promised to ban so-called conversion therapy in July 2018, under former Prime Minister Theresa May, causing Christians to fear the criminalisation of ordinary Christian practices like prayer and pastoral counselling, as well as parenting in line with their religious beliefs.

The Christian Institute has repeatedly called on the government to ditch the plans, describing them as "ideological and restrictive". 

It sought a legal opinion from Jason Coppel KC, who concluded that the proposals are likely to violate human rights conventions.

Commenting on the introduction of Baroness Burt's bill, The Christian Institute's Simon Calvert said there was no need for any new laws. 

He warned of serious implications for a variety of freedoms.

"All the abusive practices you would expect to be banned are banned. What activists want is not a law against abuse, it is a law against disagreeing with Stonewall orthodoxy in your conversations with gay or trans people," he said.

"As Jason Coppel KC has made clear, any legislation going further than the existing law would seriously impact free speech, religious freedom, freedom of association, and the rights of parents."

It is expected that the House of Lords will debate the proposals in the new year.